Sounds like I have the exact same problem. I recently upgraded from a 2011 MBP 13" to a 2018 MBP 15". Rhino worked perfect on my previous Mac, but it doesn’t work well when I try to pan on my new Mac. It’s the same with both Rhino 5 and 6.
Seems be the same as this one - Trackpad Navigation Changes Overnight and this one back from 2014 as well Trackpad Rotate &/or Pan Not Working
Be sure to write it here if you find a solution